As a semiconductor device is micronized, the influence of micro roughness of the surface of a bare wafer or a wafer with film on electrical characteristics increases. Since the micro roughness is produced in processes such as polishing, cleaning, film formation and heat treatment, in order to improve the performance and yield of a device, it is necessary to measure the micro roughness of the wafer surface in each process and to appropriately control the process condition.
Since the height of the micro roughness is as very small as from sub-nanometer order to nanometer order, an AFM (Atomic Force Microscope) is generally used and 3D coordinates are measured. However, since the AFM takes a long time for measurement, it is substantially impossible to measure the entire wafer surface.
On the other hand, it is known in the past that the micro roughness is correlated with light scattering. A micro roughness measuring apparatus using light scattering is disclosed in, for example, U.S. Pat. No. 7,286,218 (PTL 5).
As other related art, PTLs 1 to 4, 6 and 7 can be mentioned.